Angiotensin II, the central regulator of the renin-angiotensin system, mediates a series of complex biological responses to maintain homeostasis. Angiotensin II also mediates growth stimulatory responses, which may play a role in the development of atherosclerosis, hypertension, and cardiac hypertrophy. These responses are predominately generated through the action of a single receptor, the AT1 receptor. The signaling mechanisms activated by angiotensin II binding to its receptor include both calcium-mediated and tyrosine kinase-mediated events. The proposal focuses on understanding the signaling mechanisms and functional outcomes of angiotensin II-mediated tyrosine kinase signaling.